insertion apparatus for aligning cage of intervertebral fusion

ABSTRACT

The present invention discloses an insertion apparatus for aligning cage of intervertebral fusion comprising a dilatation set having a first and a second dilatation barrel formed with corresponding cross-sections and sleeved in series; a guiding set having a first and a second guiding tube inserted in the respective dilatation barrels, a guiding hole disposed adjacent to one end of the second guiding tube, a smooth curved surface inside the guiding hole communicated with a shaft hole disposed in the second guiding tube; an insert set having a leading rod inserted in the second guiding tube, a push rod pivoted at the leading rod; and a fusion cage disposed in the second guiding tube, an arc portion of the fusion cage passed through the second guiding tube along the smooth curved surface and the guiding hole, so as to shorten surgery time and position the fusion cage more exactly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a device for aligning cage of intervertbral fusion, and more particularly to an insertion apparatus for aligning cage of intervertbral fusion capable of shortening surgery time and enhancing the post-operative effect.

2. Description of the Related Art

Intervertebral disc degeneration of human body is one of common degenerative diseases in middle and elder age group. It always has good therapeutic effect for intervertebral disc degeneration by spinal interbody fusion operation. During the spinal interbody fusion, there is common usage of inserting a cage into the intervertebral disc to hold open vertebral body and maintain disc height, so as to achieve the effects of making the nerve root decompressed, pain relieved and grafting of the intervertebral segments.

There are three different approach routes of the spinal interbody fusion including anterior, posterior and poster-lateral. Each has its own cage types and quantities. The poster-lateral interbody fusion (disclosed as U.S. patent 2004/0106997) can perform minimal invasive surgery and achieve the effects of keeping away from key organs and shortening bed rest time. Therefore, most medical institutes suggest using the poster-lateral interbody fusion.

The above mentioned poster-lateral interbody fusion is performed by placing one single cage. For enhancing the stability, banana-like shaped cage has been paying more attention gradually (disclosed as U.S. Pat. Nos. 6,143,032, 6,648,915, and D533,277).

However, because the operating angle of the above mentioned poster-lateral interbody fusion with banana-like shaped cage is limited, the cage is hard to place between the intervertebral discs by the way of bilateral symmetry in the anterior location. Especially, when the cage will be applied through a percutaneous endoscopic route, A special designed apparatus is required for proper localization of the cages.

SUMMARY OF THE INVENTION

It is an objective of the present invention to provide an insertion apparatus capable of adjusting the operating angle when an arc cage is placed in vertebral body and adaptive for the postere-lateral interbody fusion through the percutaneous endoscope.

To achieve the above objectives, the insertion apparatus adaptive for spinal interbody fusion comprises a dilatation set having a first dilatation barrel and a second dilatation barrel sleeved in series, the first dilatation barrel formed with a circular inner cross-section and an elliptic outer cross-section, the second dilatation barrel sleeved outside the first dilatation barrel and formed with an elliptic inner cross-section and a circular outer cross-section; a guiding set having a first guiding tube inserted in the second dilatation barrel and a second guiding tube inserted in the first dilatation barrel, a guiding hole disposed at an outer edge adjacent to one end of the second guiding tube, a smooth curved surface disposed inside the guiding hole communicated with a shaft hole disposed in the second guiding tube; an insert set having a leading rod inserted in the second guiding tube, an outside end of a push rod pivoted at an inside end of the leading rod; and a fusion cage disposed in the second guiding tube and pushed against the push rod moving therein, an arc portion disposed at an outer edge of the fusion cage is passed through the second guiding tube along the smooth curved surface and the guiding hole and adjusted to a predetermined angle. Therefore, when operating the insertion apparatus, it can shorten the surgery time and position the cage exactly.

A best illustrative embodiment of the invention with drawings is described as below.

BRIEF DESCRIPTION OF THE DRAWINGS

All the objects, advantages, and novel features of the invention will become more apparent from the following detailed descriptions when taken in conjunction with the accompanying drawings.

FIG. 1 shows a assembly drawing of the dilatation set of a best embodiment in accordance with the invention;

FIG. 2 shows an exploded drawing of the dilatation set of the best embodiment in accordance with the invention;

FIG. 3 shows an axial sectional drawing of the dilatation set of the best embodiment in accordance with the invention;

FIG. 4 shows a sectional drawing of the dilatation set of the best embodiment in accordance with the invention along 4-4 direction of FIG. 1;

FIG. 5 shows an exploded drawing of the guiding set of the best embodiment in accordance with the invention;

FIG. 6 shows an axial sectional drawing of the guiding set of the best embodiment in accordance with the invention;

FIG. 7 shows an exploded drawing of the insert set of the best embodiment in accordance with the invention;

FIG. 8 shows an axial sectional drawing of the insert set of the best embodiment in accordance with the invention;

FIG. 9 shows a sectional drawing of the fusion cage of the best embodiment in accordance with the invention;

FIG. 10 shows a sectional drawing of the rotating ring of the best embodiment in accordance with the invention; and

FIG. 11 shows a schematic diagram of the best embodiment in accordance with the invention when in use.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Firstly, please refer to FIGS. 1 and 2, the insertion apparatus adaptive for the spinal interbody fusion of the present invention mainly comprises a dilatation set 20 for expanding the distance between two vertebral bodies temporarily, a guiding set 40 for forming the path provided a device to pass in and out, and a insert set 60 for inserting a fusion cage 80 between two vertebral bodies.

Before operating the present invention, patient's back is cut an opening (the surgical method is disclosed by U.S. patent 2004/0106997) and insert position and direction are detected by a test rod (not shown).

Referring to FIGS. 3 and 4, the dilatation set 20 includes a first dilatation barrel 22, a second dilatation barrel 24 sleeved with the first dilatation barrel 22 each other, and a handle 26 driven the first dilatation barrel 22 to rotate. The first dilatation barrel 22 has a circular inner cross-section and an elliptic outer cross-section, the second dilatation barrel 24 sleeved outside the first dilatation barrel 22 has an elliptic inner cross-section and a circular outer cross-section, and the handle 26 has a through hole 260 provided for the first dilatation barrel 22 to pass. In this embodiment, since the outer cross-section of the first dilatation barrel 22 and the through hole 260 of the handle 26 are elliptic, they can match each other to form transmission status, but not limit thereto.

The operation process of the dilatation set 20 is extending the first dilatation barrel 22 along the test rod to make the distal end of the first dilatation barrel 22 place between two vertebral bodies, and covering the handle 26 to rotate 90 degree for setting against adjacent up and down vertebral bodies with the corresponding outer edge along long axis of the elliptic cross-section of the first dilatation barrel 22, so as to expand the distance between two vertebral bodies to achieve the effect of shortening surgery time. The distance between two vertebral bodies is further expanded by sleeving the second dilatation barrel 24, and then the first dilatation barrel 22 is removed.

Referring to FIGS. 5 and 6, the guiding set 40 comprises a first guiding tube 42 and a second guiding tube 44 sleeved with each other. An inner axial hole of the second guiding tube 44 is rectangular. A guiding hole 440 formed adjacent to the distal end of the second guiding tube 44 communicates between the outer edge and rectangular axial hole of the first guiding tube 42, and a smooth curved surface is formed therebwteen.

The operation process of the guiding set 40 is extending the guiding set 40 along the second dilatation barrel 24 to between the expanded two vertebral bodies, and removing the first guiding tube 42 but keeping the second guiding tube 44 to make the distal end of the guiding hole 440 place in the gap between the two vertebral bodies.

To prevent the sharp edge portion of the guiding hole 440 from injuring body organs, the present invention further comprises an inner guiding rod capable of reciprocating inside the second guiding tube 44, and a support piece 48 disposed at the distal end of the inner guiding rod and formed a curved surface portion thereon to fill inside the guiding hole 440, so as to couple with the inside peripheral wall of the guiding hole 440 to form a smooth surface to prevent from injuring human body. After the second guiding tube 44 is set in position, remove each inner guiding rod 46 and support piece 48.

Referring to FIGS. 7 and 8, the insert set 60 comprises a leading rod 61 with hollow inside and capable of reciprocating in the second guiding tube 44, a push rod 62 with hollow inside and an out side end pivoted at the inside end of the guiding rod 61, a hollow hammer sleeve 63 having one end screw with the outside end of the leading rod 61, a block ring 64 disposed inside the hammer sleeve 63 and having a hexagon concave hole 640 disposed at the outside end of block ring 64 exposed out of the hammer sleeve 63, a flexible element 65 having one end fixed at the inside end of the block ring 64 and the other end extended along the inside of each hollow leading rod 61 and push rod 62 to the out of the distal end of the push rod 62, and a coil spring 66 disposed between the preferred position of the hammer sleeve 63 and the block ring 64 and constantly forced the block ring 64 toward the outside end of the block ring 64.

Referring to FIGS. 9 and 10, the fusion cage 80 comprises an arc portion formed at the outer edge capable of sliding along the guiding hole 440 and having a plurality of hollow portions corresponding to the tooth-shaped protruding portions 82 disposed at the surfaces of the two adjacent vertebral bodies contacted with the cage 80. And a rotating ring 84 is pivoted at one end of the fusion cage 80 and having a circular peripheral with a screw hole 840 to screw with the distal end of the flexible element 65, and a long groove 842 extended a preferred radian along its peripheral and providing a convex block 800 preset inside the fusion cage 80 to embed therein so as to limit the swing range of the fusion cage 80 relative to the distal end of the flexible element 65. By means of the tension of the coil spring 66, it forced the fusion cage 80 to lean closely against the distal end of the push rod 62 via the block ring 64 and flexible element 65.

The operation process of the fusion cage 80 is fixing the fusion cage 80 at the distal end of the flexible 65, setting against the outer edge of the push rod 62, and then inserting the assembly of each leading rod 61, push rod 62 and fusion sage 80 together into the second guiding tune 44. Next, force the fusion cage 80 to slide out of the second guiding tube 44 through the curved surface of the guiding hole 440 via each leading rod 61 and push rod 62 and into the gap between the expanded two vertebral bodies. In the process, the fusion cage 80 changes the angle gradually to arrive at the predetermined angle.

If necessary, the operator can pull the flexible element 65 by the block ring 64 to adequately adjust the position of the fusion cage 80. After the fusion cage 80 is positioned (shown as FIG. 11), the operator can release the fusion cage 80. The process is using a hexagon wrench to turn the block ring 64 and drive the flexible element 65 to rotate, and then releasing the fusion cage. Next, the insertion process is finished by pulling out each insert set 60 and second guiding tube 44 in series.

According to above mentioned structure, there are at least three advantages for applications listed as below: 1. expanding the gap between two vertebral bodies to shorten surgery time by the first dilatation barrel 22 with elliptic outer edge; 2. making the arc-shaped fusion cage 80 get forward along an arc path to between vertebral bodies and change the angle simultaneously to position almost at the status of bilateral symmetry relative to the vertebral bodies by the arc guiding hole 440 disposed at side of the second guiding tube 44; and 3. positioning the fusion cage 80 more exactly by the flexible element 65 extended in the hollow insert set 60.

Although the invention has been explained in relation to its preferred embodiment, it is not used to limit the invention. It is to be understood that many other possible modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the invention as hereinafter claimed. 

1. An insertion apparatus for aligning cage of intervertebral fusion, comprising: a dilatation set having a first dilatation barrel and a second dilatation barrel sleeved in series, the first dilatation barrel formed with a circular inner cross-section and an elliptic outer cross-section, the second dilatation barrel sleeved outside the first dilatation barrel and formed with an elliptic inner cross-section and a circular outer cross-section; a guiding set having a first guiding tube inserted in the second dilatation barrel and a second guiding tube inserted in the first dilatation barrel, a guiding hole disposed at an outer edge adjacent to one end of the second guiding tube, a smooth curved surface disposed inside the guiding hole communicated with a shaft hole disposed in the second guiding tube; an insert set having a leading rod inserted in the second guiding tube, an outside end of a push rod pivoted at an inside end of the leading rod; and a fusion cage disposed in the second guiding tube and pushed against the push rod moving therein, an arc portion disposed at an outer edge of the fusion cage is passed through the second guiding tube along the smooth curved surface and the guiding hole and adjusted to a predetermined angle.
 2. An insertion apparatus for aligning cage of intervertebral fusion as claimed in claim 1, wherein an inside cross section of the second tube is corresponding to a predetermined shape of the outer edge of the cage fusion.
 3. An insertion apparatus for aligning cage of intervertebral fusion as claimed in claim 2, wherein the inside cross section of the second tube is rectangle.
 4. An insertion apparatus for aligning cage of intervertebral fusion as claimed in claim 1, wherein the guiding set is further including an inner guiding rod inserted in the second guiding tube by reciprocating, and a supporting piece disposed at the inner guiding rod and neighbored on an inner edge of the guiding hole.
 5. An insertion apparatus for aligning cage of intervertebral fusion as claimed in claim 1, wherein the inert set is further including a hammer sleeve with pipe shape screwed with the leading rod by threads, a block ring having a predetermined part inserted in the hammer sleeve, a spring disposed between the block ring and the leading rod, and a flexible element having an outside end fixed with the block ring and an inside end pivoted on a predetermined part of the cage fusion.
 6. An insertion apparatus for aligning cage of intervertebral fusion as claimed in claim 5, wherein a plurality of protruding portions are disposed at two surface of the cage fusion disposed at each corresponding vertebral body.
 7. An insertion apparatus for aligning cage of intervertebral fusion as claimed in claim 5, wherein the predetermined part of the cage fusion is pivoted a rotating ring having a screw hole screwed at the inside end of the flexible element and a long groove extended a predetermined length along a circular outer edge of the rotating ring, the long groove provided a convex block preset on the cage fusion to embed therein for limit a swing range of the rotating ring.
 8. An insertion apparatus for aligning cage of intervertebral fusion as claimed in claim 1, wherein the dilatation set further including a handle having a through hole with non-circular inside cross section, and an one end of the first dilatation barrel has a corresponding shape for inserting in the through hole, so that the handle is able to drive the first dilatation barrel and rotate with it. 